Lock



March 12, 1929. F. E THOMPSON 1,705,344

LOCK

Filed Jan. 6, 1.927

Patented Mar. 12, 1929.

urrEo STATES PATEN FRANK E. THOMPSON, OF STAMFORD, CONNECTICUT, ASSIGNOR TO THE YALE & TOWNE V "Flea.

MANUFACTURING COMPANY, OF STAMFORD, CONNECTICUT.

LOCK.

Application filed January 6, 1927. Serial no. 159,414.

This invention relates to improvements in locks and more particularly those of the cylinder type,one object of the invention being to provide simple means to effectually lock the plug against turning upon attempted surreptitious manipulation of the lock.

A further object is to utilize a portion of the plug to provide means cooperable with the cylinder to lock the plug against. turning, upon attempted forcible operation of the lock.

With these and other objects in view, the invention consists in certain novel features of construction and combinations of parts as hereinafter set forth and pointed out in the claims.

In the accompanying drawings:

Figure 1 is a fragmentary sectional View of a cylinderlock structure embodying my invention; I

Figure 2 is atrans verse sectional View;

Figure 3 is a fragmentary longitudinal section, illustrating the'inode of operation of my improvements, and

Figure t is a detail fragmentary View of the plug. V

l lock cylinderis indicated at 1 and in its inner face a groove or recess 2 is formed, for a purpose hereinafter explained and the cylinj der is also provided with tumbler receiving recesses 1. The plug of the lock is shown at 3 and provided with a head 4 and a divided ring 5, which latter enters a groove 6 in the plug. The rib portion 3 of the plug 8 is cut away at one end as at 7 and formed with a weakened portion, as a tongue 8 projecting into the cut-away portion, and forming one of the ribs of the plug.

Normally the parts are in the positions shown in Figure 1 and the tongue will in no way interfere with the normal operation of the lock, but should attempt be made to force the lock with the use of a screw-driver or other device, as illustrated in Figure 3, the weakened portion of the plug, viz, the tongue 8, will be forced outwardly and a portion 8* thereof caused to enter the recess 2 in the cylinder wall. The plug will now be in such relation to the cylinder that it will be effectually locked against turning and normal operation of the lock to retract a bolt, Wlll. be prevented.

I do not in this case claim broadly means controlled by attempted surreptitious operation of the lock to block the effective operation ofthe bolt operating means, the same being contemplated by copending application filed even date herewith and designated by Serial No. 159,422, nor broadly to means carried by the plug adapted to be'caused to interlock with the cylinder, the same being contemplated by .copending application filed even date herewith bv Frederic K. Heyer and designated by Serial No; 159,423.

Having fully described my invention whatand said plug having an integral weakened part adapted to be forced into said recess upon attempted.surreptitious operation of the lock.

3. The combination of the cylinder and plug of a lock, said cylinder havingarecess and said plug having a tongue to be forced into said recess in the cylinder to lock the plug to the cylinder upon attempted sun. I

reptitious operation of the lock. v

4. The combination of the cylinder and plug of a lock, said cylinder having a recess and said plug having internal ribs, and a tongue at one end portion of the plug, said tongue forming one of the ribs of the plug and adapted to be forced to engage in the recess of the cylinder upon attempted surreptitious operation of the lock.

5. The combination of the cylinder and plug of a lock, said plug having a head and the cylinder having a recess inwardly of said head, said plug'having a part to be forced to engage in said recess and behind the head on the plug upon attempted surreptitious operation of the plug.

In testimony whereof, I have signed this i specification.

FRANK E. HOMPSON; 

